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COMPRESSION AND VAGUUM PUMP. No. 504,094. Patented Aug. 29, 1893.

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GOMPRESSION AND VACUUM PUMP.

- 'No. 504,094. Patented Aug.- 29,1893.

UNITE PAUL I. SOI-IMALTZ, HAMBURG, GERMANY.

COMPRESSION AND V ACUUM PUMP.

SPECIFICATION forming part of Letters Patent No. 504,094, dated August29, 1893.

Application filed December 29, 1891. Serial No. 416,466. (No model.)Patented in Germany June 14, 1891, No. 61,104.

and February 6, 1892, No. 64,656.

To all whom it may concern.-

Be it known that I, PAUL I. SCHMALTZ, a subject of the German Emperor,residing in Hamburg, in the Empire of Germany, have invented certain newand useful Improvements in Compression and Vacuum Pumps, (for which Ihave obtained Letters Patent of Germany, No. 61,104, dated June 14,1891, and No. 64,656, dated February. 6, 1892,) of which the followingis a specification.

This invention relates to certain improvements in the lubricating andsealing of compression and vacuum -pumps. Heretofore different methodswere used for removing the heat of compression in such pumps, namely,-first, the circulation of a lubricating liquid of low temperature withthe gases through the cylinder of the pump; secondly, the injection andevaporation of some portion of a liquefied refrigerating medium at theinside of the compressor; thirdly, the cooling of the outside of thecompressor by water, which is sometimes assisted by the cooling ofthe'interior of the piston that is closed toward the walls of thecompressor.

This invention is designed to effect the sealing and lubricating of thewalls of the compressor-cylinder and of the piston and pistonrod, and itconsists in arranging the piston with one or more chamberswhioh are opentoward the walls of the compressor but incased by the piston-rings, andin keeping the space in these chambers filled with the cooledlubricating liquid and renewing the latter while the piston passes overone or more ports in the walls of the compressor. The lubricating liquidabsorbs, during the up and down stroke of the piston, the heat ofcompression which has been transmitted to the walls ofthecompressor-cylinder and affords ample lubrication while it cannotdetract from the efficiency of the compressor as very little of .dhelubricating liquid is carried 011* with the gases so as to exert aninjurious influence in scribed hereinafter and finally pointed outin theclaims.

In the accompanying drawings, Figure 1 represents a side-elevation,partly in section, of a refrigerating plant, which shows also theconnection of the compressor with the cooling-tank for the lubricatingliquid. Fig. 2 shows a side-elevation of a horizontal compression orvacuum-pump with myimprove'd means for lubricatingand sealing the pistonand piston-rod of the same. Fig. 3 is a vertical longitudinal section ofthe pump, shown in Fig. 2. Figs. 4, 5 and 6 are vertical transversesections, respectively on lines 4, 4, 5, 5 and 6, 6, Fig. 3; and Figs. 7and 8 are vertical transverse sections of a vertical gas-compressor,taken on planes at right-angles to each other. Fig. 9 is a verticalcentral sec tion of an upright gas-compressor, showinga modifiedarrangement of the liquid-supply valves. Fig. 10 is a horizontal sectionthrough the compressor-cylinder and piston, on line 10, 10, Fig. 7; andFigs. 11, 12 and 13 are detail side-views showing different forms ofpistons.

Similar letters of reference indicate corresponding parts.

0 in the drawings represents a compressor,

.whichmay be of the horizontal or vertical type, P a circulating-pumpfor the lubricating liquid, which pump isconnected with thecompressor-cylinder and with a cooling-tank T for the lubricatingliquid, the upper end of the tank being connected by a pipe with thecompressor.

S S represent separators which are interposed respectively between thecompressor and the condenser and refrigerator, one of said separatorsserving for collecting the liq uid carried along with the gases, theother' for collecting the liquid deposited on the inside of the coils ofthe refrigerator, which is produced by means of a reversing-device R,shown in Fig. 1. This reversing-device is fully described and claimed ina separate application, Serial No. 411,863, filed November 14, 1891.

The separators SS are connected with the tank T for the lubricatingliquid by means IOO oit the lubricating liquid collected in the same atproper intervals of time.

The lubrication of the compressor-walls is produced by arranging in thepiston B a chamber or chambers b, which are open toward the walls of thecompressor, but which are inclosed toward the interior of thecompressor-cylinder A. by piston-rings b. The chambers in the piston Bare supplied with a lubricating liquid by the circulating-pump P, or bygravity if the cooling-tank is arranged at a higher elevation than thecompressor. The pump P is connected bya suppl y-pipe d with oil-channelsd that comm unicate with the interior of the compressor-cylinder bymeans of ports a a which are arranged with or without valves accordingto the length of the chambers in the piston B. The oil-channes d arealso connected by channels 01 with one or more chambers arranged in thestutling-box Got the piston-rod D, the cylinder A having alsooutlet-ports a through which the lubricating-liquid leaves the chamberor chambers in the piston, it being then returned by a suitable pipe dinto the cooling-tank by the circulating-pump or by pressure, as thecase may be. When the ports are not provided with valves, thepiston-chambers have to be long enough so as to establish the regularsupply of the lubricatingliquid during the strokes of the piston, whilewhen the ports are valved, they are made to open for the period duringwhich the chambers of the piston are opposite the ports, the ports beingkept open as long as the piston is in connection with them. It isevident that this arrangement may be used with single-acting ordouble-acting compressors, both of the vertical and horizontal type,also with single-acting compressors of the box-type in which latter typethe lubricating liquid is conducted from the piston-chambers through anoverflow-channel into the crank-pit or into a special collectingchamber.

The compressor-cylinder A is preferably provided with cushionedsafety-heads A near the outlet-valves for the compressed gas, so as toprevent accidents which might be caused by drippings of the lubricatingliquid passin g between the walls of the compressor-cylinder and thepiston-rings, said safety-heads yielding sufticiently to permit theaccumulations to escape. In a horizontal compressor the safety-heads Aare arranged at both ends of the cylinder A and cushioned by means ofhigh pressure gas which is conducted into the hollow safety-heads bysuitable ducts a connected with the pressure-side of the compressor, asshown in Fig. 3. The safety-head A adjacent to the stuffing-box of thepistonrod is not effected by the spring in the latter, which springserves merely for exerting a pressure on the packing of thestuffing-box, as the cushioning of the safety-head is entirelyaccomplished by the high pressure gas in the same.

The gas inlet and outlet valves are arranged, whenever possible, in onecasing with one port in common, which arrangement permits the drippingsto fill this port on the dischargestroke, and empty back into thecompressor during the suction-stroke of the piston, as shown in Fig. 9.Some of the drippings pass by, even with the best of constructions, andthis quantity will be sufficient to stop the clearances eifectively.

The lubrication of the piston-rod is effected by introducing a portionof the liquid from the cooling-tank into a chamber of the stuffing-box,or by introducing the liquid after it has passed through the chambers ofthe piston where it has become heated to some extent and most of thegases have been driven otf from the liquid by such heat, into thechambers of the stufling-box. The latter arrangement is to some extent asafety-guard against the escape of gases which are absorbed by thelubricating liquid and of which a small portion always escapes throughthe stuiiing-box of the piston-rod. The lubrication of the piston-rodcan also be etfected by a chamber which communicates with the inside ofthe compressor, whereby a portion of the liquid will always surround thepistonrod.

In the compressor shown in Figs. 2 to 6, the cylinder A is arranged in ahorizontal position and provided with two inlet-ports a, and twooutlet-ports a, for the lubricant, two on each side of the verticalplane of the cylinder, which ports communicate with a circumferentialchamber at the middle part of the pistonB as the same passes over saidports. The supply of liquid to the ports and pistonis regulated by meansof oscillating valves e e that are operated by a suitable valve-gearconnected with an eccentric on the driving shaft, as shown in Fig. 2.The cold liquid is supplied from the cooling tank to the supply-port aat one side of the center of the cylinder and into the annularcircumferential chamber of the piston as the same passes over said port.The liquid by the action of the pump passes then around the piston,takes up the heat of compression and passes out through thedischarge-ports a at the-other side of the center of the cylinder to thereturn-pipe d for the heated. liquid. When the piston arrives at theother end of the cylinder A, the liquid passes through the longitudinalchannel f and the second inletport aof the piston and into the chamberof the same, passing out through the port a, a second longitudinalchannel f and the discharge-pipe d to the tank T. The liquid passesthrough the connecting-pipef to the channel (1 that communicates withthe annular chamber in the stoning-box O of the piston-rod D, as shownclearly in Figs. 3 and 5, whenever the piston is not in position overthe inlet and outlet-ports a a. The liquid is returned through a secondchannel 01 pipe IIO f longitudinal channel f and return-pipe d to thecooling-tank. The oscillating motion of the liquid supply-valves is sotimed that the ports of one valve are open so as to supply oil to thepiston when the same arrives at one end of the cylinder, duringwhichtime the ports of the second valve are closed, while when the piston-rodis at the other end of the cylinder the ports of the valve at that endare open so as to supply cold liquid, in which position the ports of thefirst valve are closed toward the cylinder but open toward the ports ofthe second valve.

The connecting-channels and valves for supplying the liquid to theannular chamber of the piston and to the chamber of the piston-rod areclearly shown in Figs. 3, 4;, 5 and 6, the liquid in said chamberstaking up the heat of compression from the walls of thecompressor-cylinder and the piston while simultaneously lubricating andsealing the piston and the piston-rod.

In compressors of the vertical type, such as are shown in Figs. 7, 8,and 9, the liquid is supplied and discharged through vertical channels gg in the wall of the compressorcylinder, one of said channels beingconnected at its upper end with the pipe 01 that conducts the coldliquid from the cooling-tank to the piston, while the other channel isconnected with the pipe (1 that conducts the heated liquid back to thecooling tank. The lower ends of the channels gg' are connected with achamber g in the stuffing-box of the piston-rod, as shown clearly inFigs. 7 and 9. The inlet and outlet-ports a a are arranged atdiametrically opposite points in the cylinder, which ports are eitherclosed by means of slide-valves h h that are operated by a suitablevalve-gear operated by an eccentric on the driving-shaft, or bypuppet-valves M, as shown respectively in Figs. 7 and 9. In either casethe lubricating liquid is supplied to the chamber b arranged at theinterior of the piston B, the cold liquid being injected at one sideinto the piston, while the heated liquid is ejected at the opposite sideof the same and then returned to the cooling-tank. The course of thelubricating liquid is indicated by arrows in the different figures, theliquid moving in acontinuous current from the supply-pipe through themain-channel, it being intermittently deflected in its course firstthrough the chamber of the piston, then forced through the chamber inthe stuffingbox, then through the piston when it arrives at its secondposition,then again through the stuffing-box, &c. from the cooling-tankunder pressure through the oil-channels, it effects asudden but forcibleaction on the comparatively small quantity of liquid in the piston so asto eject the same and produce thereby the quick-exchange of the cooledliquid with the heated liquid,

which would otherwise not be possible owing to the short duration of theconnection of the As the liquid is conducted piston with the supply anddischarge-ports a a in the cylinder. As the liquid is moved by thecirculating-pump under pressure and under exclusion of the atmospherethrough the supply and discharge-channels of the compressor-walls andthrough the chambers of the piston and stuffing box of the piston-rod,the effective cooling, lubricating and sealing of the compressor-walls,safety-heads, piston and piston-rod are accomplished. The heat ofcompression is therefore efiectually taken up and the loss of'liquidconsiderably decreased, as amuch smaller quantity of the same is carriedalong by the gases to the other parts of the refrigerating-machine,while there is a comparatively smaller loss of gas by leakage to theatmosphere. Whatever liquidis carried along by the gases is collected inthe separators S S and returns by pipe-connections to the compressor andcooling-tank, as shown in Fig. 1. In this connection it may be statedthat by lubricating liquid any suitable lubricating-oil or a mixture ofoil with other lubricants, or with a refrigerating-liquid, which latterwould expand in the piston and would be pumped off by an auxiliary pump,is meant.

In connection with the cooling-action of the liquid, aliquid-refrigerant may be injected into the compression-space of thecylinder, so as to produce the cooling of thevapors, and it may also beinjected intermittently or continuously in the suction-space of thecylinder, so as to reduce the pressure on the valves and cool off theheated gases in'and near the compressor.

The term chamber or chambers of the piston is intended to comprise theinterior chamber or chambers and the exterior annular chamber, or anumber of smaller annular chambers, as shown respectively in the detailFigs. 11, 12 and 13.

Having thus described my invention, what I claim as new, and desire tosecure by Let ters Patent, -is

1. The combination, in a compression or vacuum-pump, of a pump cylinderhavingv supply and discharge channels, inlet ports for theIub'ricating'liquid on one side and outlet ports for the lubricatingliquid on the reverse. side thereof, a piston havingachamber which isopen toward the walls of the'pump, and a stuffing-box for. thepiston-rod having a chamber connected with the supply and dischargechannels, whereby the lubricating liquid is der, supply and dischargechannels for the lubricating liquid arranged respectively on each sideof the pump, longitudinal channels connecting the ports on one side witheach other and with the channels on that side, and valves for openingand closing said ports intermittently, substantially as set forth.

3. The combination, in a compression or vacuum-pump, of a pump cylinderhaving inlet ports for the lubricating liquid on one side, outlet portsfor the lubricating liquid on the reverse side thereof, a piston havingone or more chambers open toward the walls of the cylinder, supply anddischarge channels for the lubricating liquid arranged respectively oneach side of the pump, longitudinal channels connecting the ports on oneside with each other and with the channels on that side, valves forintermittently opening and closing the ports, and a valve gear foroperating said valves, substantially as set forth.

4. The combination, in a compression or vacuum pump, of a pump cylinderhaving inlet ports for the lubricating liquid on one side, outlet portsfor the lubricating liquid on the reverse side thereof, a piston havingone or more chambers open toward the Walls of said cylinder, supply anddischarge channels for the lubricating liquid,a chamber in thestuffing-box of the piston-rod, channels for connecting said chamberwith the supply and discharge channels of the liquid supplied to thepiston, valves for said ports, a cooling tank for said liquid, and pipesfor connecting the tank with the supply and discharge channels of thepump, substantially as set forth.

5. The combination, in a compression or vacuum-pu mp, of a pumpcylinder, inlet ports for the lubricating liquid on one side, outletports for the lubricating liquid on the reverse side thereof, a pistonhaving one or more chambers open toward the walls of said cylinder,supply and discharge channels for the lubricating liquid, hollowcushioned safety heads at the ends of said cylinder, and ducts, as aleading from the pressure side of the compressor to the hollow safetyheads.

6. In a compression or vacuum pump, the combination of a piston havingclosed ends and provided with a circumferential chamber, a receptaclefor a lubricating medium provided with a cooling device for saidlubricating medium, a channel or port in the compressor wall throughwhich said lubricating medium is supplied to said circumferentialchamber, and adj unctive connections whereby said lubricating medium issupplied to said circumferential chamber.

7. In a compression or vacuum pump, the combination of a piston havingclosed ends and provided with a circumferential chamber, a receptaclefor a lubricating medium, means for circulating said lubricating medium,a separator for separating said lubricating medium from the gas of thepump, channels or ports in the compressor walls throughwhich saidlubricating medium passes to and from said circumferential chamber, andadj unctive connections whereby said lubricating medium is supplied toand returned from said circumferential chamber.

8. In a compression or vacuum pump, the combination of a piston havingclosed ends and provided with a circumferential chamber, a receptaclefor a lubricating medium, a stuifing box for the rod of the pistonprovided with a chamber for the lubricating medium, a channel or port inthe compressor wall through which said lubricating medium is supplied tosaid circumferential chamber, and adjunctive connections whereby saidlubricating medium is supplied to the chamber of the stuflingbox and tothe circumferential chamber.

9. In a compression or vacuum pump, the combination of a piston providedwith a circumferential chamber, channels or ports in thecomprcssor wallsthrough which a lubricating medium is supplied and discharged to andfrom the chamber of said piston, and valves by which said channels orports are intermittently opened and closed as said piston is moved.

10. In a compression or vacuum pump, the combination of a piston withclosed ends and provided with a chamber opening to the wall of thecompressor, inlet and outlet ports in the compressor for a lubricatingmedium, supply and discharge channels for said lubricating medium, astuffing box for the rod of the piston provided with a chamber, channelsfor connecting said chamber of the stuffing box with the channels ofthe'lubricating medium supplied to the piston chamber, valves for saidinlet and outlet ports of the compressor, a cooling tank for saidlubricating medium, and pipe connections between said cooling tank andthe supply and discharge channels of the pump.

11. The combination, of a compression or vacuum pump, a piston having achamber in the same, said chamber being open toward the walls of thecylinder, inlet ports for the lubricating liquid on one side of thecylinder, outlet ports for the lubricating liquid on the reverse sidethereof, supply channels for conducting the liquid to the inlet ports,discharge channels for the outlet ports, longitudinal channels forconnecting the ports and channels on one side, a stufiing-box around thepiston-rod, a chamber therein, channels leading to said chamber, andconnecting pipes connecting the channels leading to said chamber, withone of the supply and discharge channels, respectively, substantially asset forth.

12. The combination, of a compression or vacuum-pump, a piston having achamber in the same, said chamber being open toward the walls of thecylinder, inlet ports for the lubricating liquid on one side of thecylinder,

IIO

outlet ports for the lubricating liquid on the reverse side thereof,supply channels for conducting the liquid to the inlet ports, dischargechannels for the outlet ports, longitudinal channels for connecting theports and chan- In testimony that I claim the foregoing as 10 v nels onone side, a stuffing-box around the my invention Ihave signed my name inprespiston rod,a chamber therein, channels leadence of two subscribingwitnesses.

in to said chamber, connectin pipes con- '1 ne hting the channelsleading to s aid chamber PAUL SGHMAL'] with one of the slipply anddischarge chan- Witnesses: nels, respectively, and valves for openingand H. KRAMER, closing said ports intermittently, substan- Baumstr,

tially as set forth. 1 MAX WISS.

